Answer:
That statement is false.
Step-by-step explanation:
Oligarchy is a system of government in which the power in the country is controlled by a small group of people (could be based on nobility, milltuiary, or education.)
Untied States was under an oligarchy government when the country is under the British' rule. But, this occurred in 1700s, not 1800s.
USA gained independence from the British government in 1776 and the country has been run with a democracy system ever since.